In order to make high data rate interactive services such as video and internet access available to more residential and small business customers, high-speed data communications paths are required. Although fiber optic cable is the preferred transition media for such high data rate services, it is not readily available in existing communication networks and the expense of installing fiber optic cabling is prohibitive. Current telephone wiring connections, which consist of copper twisted-pair media, were not originally designed to support the data rates or bandwidth required for interactive services such as video on demand or even high speed internet connections. Asymmetric Digital Subscriber Line (ADSL) technology has been developed to increase the effective bandwidth of existing twisted-pair connections, allowing interactive services to be provided without requiring the installation of fiber optic cable.
Discrete multi-tone (DMT) is a multi-carrier technique which divides the available bandwidth of twisted-pair copper media connections into mini-subchannels or bins. The DMT technique has been adopted in the ANSI T1.413 standard (ADSL standard). In the ADSL standard, DMT is used to generate 250 separate 4.3125 kilohertz subchannels from 26 kilohertz to 1.1 megahertz for downstream transmission to an end user. Likewise, DMT is used to generate 26 subchannels from 26 kilohertz to 138 kilohertz for upstream transmission by an end user. The asymmetric transmission protocol implemented by the ADSL standard requires a higher rate of data transmission from a central office to a remote terminal and a lower rate of data transmission from a remote terminal to a central office. As a result, different processing sequences are required at the remote terminal and central office ends. Currently available systems utilize printed circuit board designs which are configured to operate as either a central office end or a remote terminal end and may not be used interchangeably as an opposite end. Thus, because such separate system designs are necessary, these separate systems must include separate design overhead, separate data bases and separate firmware files. Furthermore, each of the separate data bases, separate designs, and separate firmware files must all be designed, produced, and maintained with finite resources.